Technical Field
The present disclosure relates to a fuel gas storage tank and a method of manufacturing the same and more particularly, to a tank that safely stores high-pressure gaseous phase fuel, and a method of manufacturing the same.
Background Art
In general, in alternative fuel gas vehicles, such as fuel cell vehicles and compressed natural gas vehicles, a configuration of a storage system differs based on the storage method of the fuel gas. Currently, the storage method of compressed gas has been a focus of vehicle manufacturers while considering cost, weight, and simplicity of the storage method. However, since gaseous phase fuel has a low energy storage density, the storage amount or the storage pressure may need to be increased to increase a travel distance of the vehicle. Since a gas storage system mounting space is limited within a vehicle, a size of the storage tank may also be limited so a higher-pressure gas may need to be stored safely.
For a composite tank of the fuel gas storage tank to withstand an internal pressure caused by the compressed gas, outer layers are reinforced with a fiber-reinforced composite material that has high specific strength and high specific stiffness, and a liner configured to maintain gas tightness is disposed under the composite layers. Further, the form of the fuel gas storage tank varies based on the material of the liner and is classified into a type with a liner made of metal, such as aluminum, and a type with a high-density polymer liner or the like. In particular, when the liner is made of metal, although the liner has relatively high safety properties, is the liner may be expensive and may have low fatigue resistant characteristics.
FIG. 5 shows a conventional fuel gas storage tank with a high density polymer liner, reference numeral 100 indicates a composite material, and reference numeral 110 indicates a polymer liner. When the liner is a high density polymer liner, the price is relatively inexpensive and the fatigue resistant characteristics are excellent, safety properties may not exist such as low permeability resistant of hydrogen (e.g., the polymer liner does not completely prevent hydrogen from permeating into the liner).
In particular, as shown in FIG. 5, the transmitted gas may remain at an interface between the polymer liner 110 and the composite material 100, and the gas may separate the composite material layer and the polymer liner layer when the tank pressure drops. Further, the gas may leak to the exterior of the tank through a flow path in the composite material. Furthermore, the transmitted gas, which has remained at the interface, may deform the polymer liner 110 in an inward direction and cause the polymer liner to buckle, as shown in FIG. 6.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.